The only way Frank and Vaner would be able to stop the Blue Lounge Pirates' advance was if they were both at least at the seventh level. However, that would mean there are at least four high level mages and fighters in a pirate crew that has maybe one or two more regular members.
The big three pirate crews also had several high level mages and fighters, most likely more than the Bunglehoppers, but medium levels were still their main fighting force. The Bunglehoppers were also famous for their outstanding individual combat ability, so if all of them were high level, they would naturally be able to pose a threat to the other pirate crews.
Stris realized he might have picked a fight he shouldn't have when he understood how much strength the Bunglehoppers had. However, it was too late to take a step back and save his subordinates' lives, so Stris decided to let things play out.
